Background: Post-operative patients with total knee replacement will experience severe pain and get limitations in mobilization, so they need support to mobilize. Objective:This study aims to determine the relationship of social support to early mobilization in patients with post total knee replacement. Reseaech methods: A quantitative research with cross sectional method within 47 respondents. The data collecting is using questionnaires, observation sheets. The sampling technique was consecutive sampling. The study population was post TKR patients at RSO Prof. Dr. R. Soeharso Surakarta. And for the data analyzing is using Spearman. Results: There is a significant relationship on social support for early mobilization. The test results obtained p- value 0,0001 < 0,05. Emotional support for early mobilization was obtained p-value 0,001 and fourth day with p-value 0,03. Instrumental support for mobilization on the third day was obtained p-value 0,001. Information support for the mobilization of the first day with p-value 0,008, the second day with p-value 0,005, on the third day with p-value 0,003, and on the fourth day with p-value 0,003. The award supports on mobilization in the third day with p-value of 0,001, and the fourth day with p-value of 0,0001. Conclusion: There is a relationship between social support for early mobilization in post Total Knee Replacement patients.